Runes

Runes are decorated pieces of whale bone that are used to acquire and improve supernatural abilities; the more powerful the ability, the more runes it requires.

In Dishonored, a maximum of 39 runes are obtainable in a single playthrough, but 58 would be needed to fully upgrade every ability to Tier II. Therefore, Corvo Attano must assign them according to the approach he favors the most.

The Outsider claims that the first Runes were created centuries ago by an ancient and long gone civilization, saying that many of the runes in Gristol were found washed up from the water.[1]

Granny Rags is able to create Runes with an ability given to her by the Outsider. [2]

In Hiram Burrows' safehouse on top of the Tower. Although it is in the Exterior map, Corvo must navigate through the Tower to reach it. Burrows will be in the same room if he has been alerted to Corvo's presence.

On the wide open plain. Note that the position is within some river krusts' attack range.

Central Rudshore

After opening the door leading to the sewer with Daud's key, immediately before reaching the exit.

Gateway Tunnel

On top of an apartment in the slum. Corvo will probably come across if he blinks toward the train.

Old Port District

In the sewers, in Granny Rags' new home, on an Outsider shrine. Corvo will need the sewer master key, which is on Granny Rags, to open the door. It is possible to steal it, kill/knock out Granny Rags, or kill Slackjaw for the key.

In the sewer where a group of survivors reside. Drop down the hole in the middle to reach it. Note that these survivors will become weepers in high chaos.